Ultrasonic tool

ABSTRACT

An ultrasonic instrument includes a tip portion, a transducer configured to convert electrical energy into vibrational energy, an acoustic transformer interconnecting the transducer and the tip portion, and a grip portion disposed at least partially about the acoustic transformer. The grip portion is coupled to the acoustic transformer via a resilient nodal coupling at a nodal region of the acoustic transformer. The resilient nodal coupling is configured to provide rotational and axial stability to the acoustic transformer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 61/537,315, filed on Sep. 21, 2011, and U.S.Provisional Patent Application No. 61/559,946, filed on Nov. 15, 2011,the entirety each of which is incorporated by reference herein for allpurposes.

BACKGROUND

1. Technical Field

The present disclosure relates to ultrasonic tools and, moreparticularly, to an ultrasonic tool, or insert, for use by dentalprofessionals for dental treatments and procedures.

2. Background of Related Art

Ultrasonic dental tools, or inserts, generally include four basic parts.The primary part comprises a laminated stack of a magnetostrictivematerial, which is activated at its frequency of resonance to generatesufficient mechanical power. The second part is a specially shaped tipthat makes contact with the treatment area. This tip provides access andadaptation to the treatment area. The third part is an acoustictransformer, often referred to as a connecting body, which connects thelaminated stack to the tip. The fourth part is a grip, which allows thepractitioner to hold and maneuver the insert during use.

Each of these building blocks for the insert has an important role inthe operation of the insert. The stack provides the necessary power todrive the tip. The acoustic transformer matches the impedance of thestack to the tip, provides amplification of the mechanical motiongenerated by the stack, and delivers coolant and lavage to the tip. Thetip transfers the mechanical motion to the treatment area, which isoften a tooth or root surface. It also directs the lavage or coolantprovided by the connecting body. The grip not only allows thepractitioner to hold the insert but is a key component since it attachesto the acoustic transformer. It is therefore critical that the gripconnect at a nodal point for the motion along the length of the acoustictransformer. Attachment to a point not on the node will dampen themotion and reduce the available power at the tip of the insert.

Cavitron® Corporation introduced ultrasonic inserts to the dental marketin the late 1950's. The first inserts were called “P” types todifferentiate them from the cutting inserts first used for cavitypreparation. Similarly as used today, the basic structure and design ofthese first inserts included four basic components: a laminated stack ofa magnetostrictive material, a working tip, an acoustic transformer orconnecting body that connects the tip to stack, and a grip allowing thepractitioner to hold the insert during use.

These original Cavitron® designs adapted a surgical steel tube todeliver water to the treatment area. Straight Permanickel® laminationswere used to generate the mechanical energy. An acoustic transformeramplified the mechanical motion generated by the stack, and a metal gripwas attached to the connecting body using a compressed O-ring.

Over the years, improvements have been in the areas of water delivery tothe treatment area. U.S. Pat. No. 3,930,173 to Banko and U.S. Pat. No.5,567,153 to Foulkes et al. describe examples of the use ofnon-concentric holes in the tip of the insert. A swivel feature thatallowed the practitioner to more easily rotate and adapt the tip alongthe line angles of teeth is described in U.S. Pat. No. 6,716,028 toRahman et al. This design forced a compromise between the ease ofrotation (generally rotational torque below 1 in-lb.) and leakage. Atlower torque levels, the risk of coolant water leakage at the point ofrotation was increased. Some designs utilize the slippage of the O-ringthat seals the insert in the handpiece. These designs use a traditionaltoroid O-ring that seals both the handpiece-insert interface andprovides a low torque rotation. They typically allow rotation within thegland area of the O-ring but are at the mercy of O-ring quality,dimensional tolerances of the O-ring, and handpiece dimensions toprovide a good seal over all operating conditions.

Early inserts also had the disadvantage of loosening of the attachmentof the grip to the insert after several sterilization cycles.Retightening was possible but alignment of the water tubing whileretightening was problematic. In addition, the tightness of the capturemechanism often resulted in instability of the grip in both the lateraland longitudinal planes. Later designs used surface indentations tominimize loosening, but these designs did not address the problems ofrotational and axial movement of the grip during use. U.S. Pat. No.3,956,826 to Perdreaux describes a method of capturing the connectingbody inside a cavity in a resin grip. While this eliminates rotationaland axial instability, it results in a hard mount of the connecting bodyat the nodal point. The end result is an improvement in the stability ofthe grip but degradation in the tip motion caused by the hard mountingof the grip to the connecting body. A hard mount also increases thetransfer of ultrasonic energy from the connecting body to the grip.

The original stack configuration for the Cavitron designs was a flatlamination without any added rigidity either along the length of thestack or in the cross-section. Some manufacturers added a “c” shape tothe stack but this added little rigidity to the stack assembly, whileother manufacturers added a “v” shape to the stack and glued thelaminations together. While this approach added rigidity to the stack,bend angles less than 100 degrees introduced increased stress to thelaminations and moved the center of gravity of the stack assembly offthe concentric line of the stack-connecting body junction.

The stack assembly in typical ultrasonic dental inserts is brazed atboth ends. The distal end has an end-ball attached to hold the ends ofthe laminations together and provide a rounded surface to minimize anydamage to the handpiece during insertion and removal. U.S. Pat. No.5,980,251 to Sullivan et al., for example, describes a method ofcreating a conductive connection of brazing material (silver solder) atboth ends of the stack. First, this is counterproductive in that itincreases the losses in the stack assembly during use. Second, itdecreases the frequency of resonance of the stack assembly because ofthe lower sound velocity of the brazing material compared to thePermanickel® laminations. Third, the phase shift of the feedback signalin ultrasonic systems is adversely affected, especially with regard tothose systems employing motional or velocity feedback.

SUMMARY

In accordance with the present disclosure, an ultrasonic dental tool, orinsert, is provided. The insert includes a notch on both sides of thedistal end of the laminated stack assembly. The notches are secured inany suitable fashion, e.g., using a high temperature heat shrinkablematerial.

In embodiments, the distal end of the stack includes an end cap. The endcap may be a molded or machined high temperature resin that providesmechanical stability of the laminations during ultrasonic activation andsterilization cycles.

In embodiments, a non-metallic or low conductivity metal rivet componentsecures the laminations in the stack assembly. The component is securedin a small diameter hole near the distal end of the stack assembly by,for example, staking, snap locking, gluing, ultrasonic welding, etc.

In embodiments, a rigid or semi-rigid tube encloses the laminations inthe stack assembly. The tube may be constructed from a high temperatureresin and/or may be formed via extruding or molding. This encasement,e.g., the tube, may further include a nodal support for the laminationsat their midpoint.

In embodiments, a resilient material captures the connecting body in thenodal area. For example, a “soft mount” configuration for the grip maybe provided, while also providing stability with minimal axial androtational movement during use.

In embodiments, the laminated stack assembly may be recess mounted tothe mesial end of the connecting body. Such a mounting allows forconcentric mounting of the stack assembly to the connecting body,resulting in minimum brazing material on the lateral sides of the stackassembly.

In embodiments, the laminations in the stack assembly define apre-determined shape that provides adequate stiffness to the laminationsto avoid deformation during use and handling of the insert.

In embodiments, the insert is rotatable 360 degrees during use withminimal torque. The use of a multi-diameter sealing component is alsocontemplated.

In embodiments, precise bending of the insert tip can be achieved at thelocation of the nodal point supports in a bending fixture.

Particular advantages and features of the above-mentioned and otherembodiments of the present disclosure are described below. To the extentconsistent, any or all of the above-mentioned embodiments (or any otherembodiments) may be used in conjunction with any or all of the otherembodiments described herein.

A typical stack comprises laminations of a Ferro-magnetic(magnetostrictive) material ranging from 0.007 to 0.010 inches thick.The industry standard size in dentistry is 0.010 inches. Thinnerlaminations are often used at frequencies higher than 25 kHz to reduceeddy-current losses. The laminated stack assemblies of an ultrasonicdental tool have the capability to outlast the tip and connecting bodyassemblies by a factor of 10 to 20 times. The endurance of the stackassemblies however, is limited by handling damage. The presentdisclosure provides a stack having both improved electro-mechanicalcharacteristics and durability. In particular, the multiple angle bendof the stacks of the present disclosure, e.g., in the form of a “Z” bendor a “W” bend, provide both lateral and longitudinal rigidity to thelaminations in the stack assembly without introducing excessive stressesalong the bends because of the large bend angles. Bend angles aretypically between 100 and 150 degrees. The basic geometry of theassemblies of the present disclosure place the center of the assembly onor close to the centerline of the connecting body-stack junction.

Typically, even slight bending of the stacks will result in a loss inmechanical output of the insert. A new stack that is bent by handlingand then re-straightened will in most cases perform like an old insertwith a tip worn beyond the recommended 2 mm length. The presentdisclosure provides a rigid or semi-rigid tubing to protect the stackduring all phases of usage. The tubing can be an extruded or a machinedpiece with an internal dimension that approximates the diagonaldimension of the stack assembly. The mesial end of the tubing isconfigured to facilitate mounting the insert into a handpiece, providesa seal for the insert-handpiece interface, and allows for relatively lowtorque rotation of the insert assembly within the handpiece. In thisconfiguration, the laminations on the stack assembly are flat and thedistal ends of the laminations are not bound together. Further, in thisconfiguration, a molded shell may be used in place of the tube. Theadvantages of the shell are the versatility of having severalcross-sectional diameters and the addition of a nodal support for thestack assembly.

Currently, applications requiring insertion and removal from a handpieceoften have interference due to the size and shape of the brazedend-ball. The present disclosure provides configurations that avoid thepitfalls of brazing the distal ends of the laminations together. Thiseliminates the possible interference fit into a dental handpiece due toan oversize endball. The use of a molded end cap, a heat shrinkablematerial, or a low conductivity pin improves assembly time and reducesthe handling cost of the stack assembly without creating interferencewith the feedback system of the ultrasonic device.

Complete dental tools are customarily referred to as “half lambda” toolsbecause they comprise two parts, where each part consists of a one-halfwavelength (half lambda) as determined by the frequency of resonance ofthe materials and the physical lengths of the components. These toolsare free to move at both ends and have two centrally locatedlongitudinal nodal points. By definition, the longitudinal motion at thenodes is zero. Any contact of the tool off the nodal points will resultin damping of the motion. Accordingly, the present disclosure provides adental tool that mounts the grip to the connecting body with a resilientnodal mount (referred to herein as a “soft mount”). One of the keyfeatures of this configuration is that it minimizes the loading effectscaused by the shifting of the nodal point during loading of the tool'stip. This configuration also minimizes the transfer of ultrasonic energyto the grip because of the high impedance presented by the resilientnodal support. Several variations of the soft mount are described ingreater detail hereinbelow. For example, in embodiments, protrusions arelocated on the connecting body in the nodal region. An extrudedresilient material is placed onto these protrusions and the assembly isplaced into the insert grip. Alternatively or additionally, inembodiments, commercially available resilient O-rings or similarcomponents may be utilized to provide a soft mount between theconnecting body and the grip. The capture mechanisms for the nodalsupports can be machined or molded.

Precise bending of the tips on the connecting body assemblies requires areliable registration point in the bending fixtures. Current insertdesigns rely on the edge of the tip shank, but these points are locatedon radii and require the operator to use an approximate reference point.The present disclosure uses nodal protrusions on the connecting bodyassembly to precisely register the connecting body in a bending fixture.This configuration allows for the interchanging of bending tool insertsfor bending of different tip styles and lengths of the assemblies.

The grip of an insert tool provides the practitioner the ability tograsp and maneuver the tool during use. The present disclosure providesa configuration that facilitates the rotation and adaptation of theworking tip along the line angles of the tooth. One of the limitationsfor all resin grips is the small cross-sectional area in the gland areaof the O-ring. This small cross-section causes problems in fluid flowacross this area during molding. The thin section also createschallenges in welding the molded grips together. To account for this,the present disclosure provides a flat seal with or without raisedcircumferential rings, which allows the use of a thicker cross-sectionin the insert grip gland area. The mounting area can be shaped to allowsmooth interfaces for the seal of the insert and a profile for thecenter of the seal that enhances both the ability to seal theinsert-handpiece interface and provide a low torque rotation.

Dental handpieces typically have a cross-section that allows formounting of a dental tool or insert with minimal space allowed for waterdelivery to the insert. When the brazed joint of the stack-connectingbody is too large, it impedes the entry of the insert into thehandpiece. This can result in reduced mechanical output at the tip dueto the damping effect when a portion of the stack assembly is loaded offthe nodal point. It can also restrict the water flow to the insertresulting in ejection of the insert due to backpressure in thehandpiece. This is aggravated with the use of the aforementioned toroidO-ring in rotational designs. The present disclosure provides aconnecting body with a recessed area that self-aligns the connectingbody and stack assembly during assembly. A further feature of thisconfiguration is that it provides an area for a braze fillet, therebyminimizing the possibility of excessive braze material at the joint.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 a is a side view of a connecting body provided in accordance withthe present disclosure and including two protrusions at the nodal pointwith a resilient material placed over the protrusions;

FIG. 1 aa is a transverse, cross-sectional view of FIG. 1 a taken at thenodal point;

FIG. 1 b is a top view of the connecting body of FIG. 1 a illustratingthe positioning of the resilient material over the protrusions;

FIG. 1 bb is a transverse, cross-sectional view of FIG. 1 b taken at thenodal point;

FIGS. 2 a is a side view of the connecting body of FIG. 1 a showncaptured by the insert grip;

FIG. 2 b is a top view of the connecting body of FIG. 1 a shown capturedby the insert grip;

FIG. 3 a is longitudinal, cross-sectional view of a bending tool usingnodal supports to register the connecting body for precise bends;

FIG. 3 b illustrates exemplary bending geometry of the bending tool ofFIG. 3 a;

FIG. 4 a is a transverse, cross-sectional view of a multi-level seal forthe insert interface with the dental handpiece;

FIG. 4 b is a top view of the insert and dental handpiece including themulti-lever seal of FIG. 4 a disposed about the interface therebetween;

FIG. 5 illustrates laminations forming a stack assembly mounted in acountersink on the connecting body of FIG. 1 a;

FIGS. 5 a and 5 b are transverse, cross-sectional view of variousconfigurations of the laminations forming the stack assembly;

FIG. 6 a is an illustration of a tubular member that mounts over thelaminated stack assembly;

FIG. 6 aa is a transverse, cross-sectional view showing the tubularmember mounted over the laminated stack assembly;

FIG. 6 b is an illustration of a two-piece molded sheath that mountsover the laminated stack assembly;

FIG. 6 bb is a transverse, cross-sectional view showing the two-piecemolded sheath mounted over the laminated stack assembly;

FIG. 7 is a top view of a notches laminated stack assembly;

FIG. 7 a is an exploded, side view of the notched laminated stackassembly of FIG. 7 and an O-ring configured for engagement within thenotches of the laminated stack assembly;

FIG. 7 b is an exploded, side view of another embodiment of a notchedlaminated stack assembly and a cap configured for engagement about anend of the laminated stack assembly;

FIG. 7 c is an exploded, side view of another embodiment of a notchedlaminated stack assembly and a cap configured for engagement about anend of the laminated stack assembly;

FIG. 8 a illustrates the positioning of resilient nodal mounts on aconnecting body without a flange;

FIG. 8 aa is an enlarged front view of the nodal area shown in FIG. 8 a;

FIG. 8 b illustrates the positioning of multiple resilient nodal mountson a connecting body with a flange;

FIG. 8 bb is an enlarged front view of the disk shown in FIG. 8 b;

FIG. 9 a is an illustration of tapered cylinder for positioning aresilient mount on a connecting body; and

FIG. 9 b is a transverse, cross-sectional view in a first direction ofthe tapered cylinder of FIG. 9 a;

FIG. 9 c is a transverse, cross-sectional view in a second direction ofthe tapered cylinder of FIG. 9 a;

FIG. 9 d is a side view of a retaining component with anti-rotation tabsfor use with the tapered cylinder of FIG. 9 a;

FIG. 9 e is a transverse, cross-sectional view in a first direction ofthe retaining component of FIG. 9 d;

FIG. 9 f is a transverse, cross-sectional view in a second direction ofthe retaining component of FIG. 9 d; and

FIG. 9 g is an enlarged, side view of the area of detail indicated inFIG. 9 f.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure are describedhereinbelow with reference to the accompanying drawings. In thefollowing description, well known functions or constructions are notdescribed in detail to avoid obscuring the present disclosure inunnecessary detail.

FIGS. 1 a and 1 aa illustrate a resilient nodal mount 12 and an acoustictransformer, or connecting body 10 having a pair of opposed protrusions13. Resilient mounts 12 fit over the protrusions 13 to provide a “softmount” to the nodal area of the connecting body 10. The preferredgeometry of the protrusions 13 is square because this shape provides thesmallest contact area between the protrusions 13 and the resilientmounts 12 and is also the easiest and least expensive to machine.However, other configurations are also contemplated. FIGS. 1 b and 1 bbillustrate the axial mounting of the resilient nodal mounts 12 onto theprotrusions 13 of the connecting body 10. The length L and the diameterD of the resilient nodal mounts 12 are determined by the maximumdiameter of the insert grip (FIGS. 2 a-2 b).

FIGS. 2 a and 2 b illustrate the mounting of the connecting body 10within the grip 20. More specifically, FIG. 2 a illustrates the nests 22of the grip 20. As shown in FIG. 2 b, the nests 22 are configured tocapture the soft mount, e.g., the resilient nodal mounts 12 attached tothe protrusions 13 of the connecting body 10. The soft mount assembly istotally contained within the nests 22. The area between the connectingbody 10, the grip 20, and the nests 22 allows the flow of coolant fluidacross the nodal mount.

FIG. 3 a illustrates a bending tool holding fixture 30 for retaining theconnecting body 10. An alignment distance L2 is defined between aregistration point 33 and the beginning of the bending point 32. Thebending arm 31 is shown in the stop position for the completed bend. Thecontra angle shown in FIG. 3 b is achieved by moving the bending arm 31upward to its vertical stop point (not shown).

An embodiment of the present disclosure for a low rotational torqueinsert is illustrated in FIGS. 4 a and 4 b, e.g., an insert requiring arotational torque of between about 0.5 in-oz and about 1.5 in-oz. Anelongated sealing gasket 40 having a body defining an internal diameter47 is provided. The elongated sealing gasket 40 defines a relativelyflat outer surface along its length and further includes a pair ofcircumferential rings defining outer diameters 42 and 41. The outerdiameter 42 of one of the rings of the sealing gasket 40 when mounted inthe gland area, e.g., recessed area, of the insert grip 20 isdimensioned to provide an easy insertion into a dental handpiece 45.This is because the outer diameter 43 is less than the inner diameter 44of the dental handpiece 45. The outer diameter 41 is also greater thanthe outer diameter 42 of the sealing gasket 40. The low rotationaltorque of the insert grip 20 is achieved by the combination of the lowfriction between the circumferential rings defining outer diameters 41and 42, and the internal diameter 44 of the dental handpiece 45. Theouter diameters 41 and 42 also provide the required seal for the insertgrip 20 when placed in the dental handpiece 45, during both static anddynamic phases of use. Although the sealing gasket 40 is shown with twocircumferential rings, the low rotational torque function iscontemplated with a single circumferential ring. It is also contemplatedthat the function can be achieved by using a sealing gasket 40 withoutadditional circumferential rings, where the machining or molding of aseal gland controls the diameter 43 thereof to have a non-uniformdiameter along its length.

With reference to FIGS. 5, 5 a, and 5 b, the present disclosure furtherprovides for improved durability of a stack assembly (stack oflaminations) 50, 51, e.g., Permanickel® laminations, although otherlaminations are also contemplated. Improved durability and improvedelectro-mechanical output is achieved by producing lamination shapeswith a minimum of two bending angles (stack assembly 51 (FIG. 5 a)) orthree bending angles (stack assembly 50 (FIG. 5 b)). The typical rangefor the angles can vary between 100 and 150 degrees. The preferredangles for the double-angle lamination stack assembly 51 are about 118degrees, while the preferred angles for the triple-angle laminationstack assembly 50 is about 136 degrees, as shown in FIGS. 5 a and 5 b,respectively. The actual bending angles are in part determined by therequired rigidity of the lamination, the thickness of the lamination,and the maximum final width of the bent lamination. The bend anglesallow the stacking of 14 to 16 laminations inside the diameter D2 of thecountersink 19 in connecting body 10, depending on the thickness of theindividual laminations comprising the stack assemblies 50 and 51. Theproximal end diameter D3 of connecting body 10 is limited by the minimuminside diameter 44 of the dental handpiece 45 (see FIG. 4 b).

A further embodiment of this disclosure provides components 62, 60 forhousing the stack assembly, e.g., stack assembly 63, as is illustratedin FIGS. 6 a, 6 aa, 6 b, and 6 bb. The use of a hollow extruded tube 62or a two-part molded sheath component 60 eliminates the need for specialshapes to the laminations. The component 62, 60 covers the stackassembly 63 and attaches to the grip 20 (FIG. 4 b). In the case of thecomponent 60, nodal supports 61 are molded at the approximate midpointof the stack assembly 63, e.g., the nodal area thereof. This addsadditional rigidity to laminations smaller than 0.010 thick. Thecomponent material's molding and welding requirements determine itsthickness. Diameter D4 of sheath component 60 is selected to interfacewith the diagonal of the stack assembly 63, such that the outer edges ofthe stack assembly 63 make contact with the sheath component 60.Diameter D5 is dimensioned to assure non-interference fit of tube 62into inner diameter 44 of handpiece 45 (see FIG. 4 b). It is alsocontemplated that molded sheath 60 have multiple diameters facilitatinginclusion of an interface sealing gasket 40 (see FIG. 4 b).

Referring to FIGS. 7 and 7 a-7 c, also provided in accordance with thepresent disclosure are embodiments configured to eliminate the endbrazing on the stack assembly, e.g., stack assembly 50 (or any othersuitable stack assembly), without creating high conductivityconnections. For example, as shown in FIG. 7 a, in one embodiment, thedistal ends of the laminations 70 a of the stack assembly are roundedand notches 71 are stamped, typically 0.100 inches, from the roundedend. The laminations 70 a are placed in a stack and a high temperatureheat shrinkable material, e.g., ring 72, is applied to the notched areato secure the distal end of the stack. In another embodiment, as shownin FIG. 7 b, the laminations 70 b are notched but not rounded. Thelaminations 70 b are placed in a stack and the distal ends are securedby placement of a cap 73. Cap 73 is configured with tabs 76 that providea snap fit to the notches 71. Cap 73 has slots 77 to facilitateattachment about the stack of laminations 70 b. A further embodiment, asshown in FIG. 7 c, includes laminations 70 c having a relatively smalldiameter hole 75 extending through the center of the radius of thedistal ends of the laminations 70 c. A component 74, e.g., a rivet, isinserted into hole 75 and is secured therein in any suitable fashion,e.g., deformation of component 74, gluing, ultrasonic welding, etc. Therivet may be formed from a low conductivity material.

A further embodiment of the present disclosure is illustrated in FIGS. 8a-8 bb. The use of resilient mounts as nodal supports requires bothaxial and rotational stability of the insert grip. In one embodiment, asshown in FIG. 8 a, connecting body 80 has a nodal area machined withmultiple flat surfaces, shown for illustration as a square area 82 (FIG.8 aa). The lead in surfaces to the nodal area 82 are shown as raisedareas 83 where the diameter of the raised areas 83 is greater than thediameter of connecting body 80 in area 84. The raised areas 83facilitate the positioning of O-ring 81 at the nodal area 82. Incombination, O-ring 81, nodal area 82, and raised areas 83 of theresilient nodal mount provide axial and rotational stability. In anotherembodiment, as shown in FIG. 8 b, the nodal area on connecting body 85includes a disk 84 defining a pair of slots (see FIG. 8 bb). Disk 84 issandwiched by O-rings 81, which in combination comprise a resilientnodal mount and provide axial and rotational stability.

A further embodiment of a resilient nodal mount provided in accordancewith the present disclosure is shown in FIGS. 9 a-9 g. In particular,the mount comprises a tapered cylinder 95 (FIG. 9 a) and a retainer 90(FIG. 9 b). This configuration is designed to compress and retain theO-rings 81 (FIGS. 8 a and 8 b). With additional reference to FIG. 8 b,tapered cylinder 95 is modified by machining a slot on the undersidethereof (see FIGS. 9 b and 9 c) to allow tapered cylinder 95 to beinserted over connecting body 85 for retention of O-rings 81. Morespecifically, two O-rings 81 are placed on connecting body 85 on bothsides of disk 84. Tapered cylinder 95 is placed between the distalO-ring 81 and the large section of connecting body 85. Retainer assembly90 is then placed over the tip end of connecting body 85 and slid intoposition to capture tapered cylinder 95. Retainer 90 is moved axiallytoward tapered cylinder 95 until fingers 94 on retainer 90 engage withthe surface of tapered cylinder 95 that defines dimension L4 on taperedcylinder 95. Once aligned, retainer 90 is moved axially along connectingbody 85 until O-rings 81 are compressed and fingers 94 snap intoposition within a recess defining dimension L5 on tapered cylinder 95.The compression surface for the O-rings 81 on tapered cylinder 95 isdefined by the difference between diameters D6 and D7 (see FIG. 9 b). Incases where the greater concentricity of the assembled parts isnecessary, an inverted split washer with an inner diameter of D7 and anouter diameter of D6 is placed between tapered cylinder 95 and O-ring81. Diameter D8 provides clearance between connecting body 85 andtapered cylinder 95. Shoulder 92 on retainer 90 provides clearancebetween assembly comprising retainer 95 and tapered cylinder 90 whenmounted in grip 20 of handpiece 45 (see FIG. 4 b).

In considering assembly of the resilient nodal mount of FIGS. 9 a-9 gonto connecting body 80 (FIG. 8 a), tapered cylinder 95 is slid over thesmall diameter of connecting body 80 with the tapered end with diameterD6 facing the distal (tip) end of connecting body 80. An O-ring 81 isplaced in the nodal area 82 and the retainer 90 is slid over the tip ofthe insert, with tabs 91 facing the distal (tip) end of connecting body80. Flanges 94 on retainer 90 are aligned to make contact with thetapered edge of tapered cylinder 95. The retainer 90 and the taperedcylinder 95 are locked together when dimension L6 on flange 94 snapsinto the gap L5 on tapered cylinder 95. Dimension L7 on flange 94 isdimensioned to allow dimension L6 on flange 94 to spread as itinterfaces with tapered cylinder 95. The dimension L8 of flange 94 isless than the gap L5 on tapered cylinder 95 allowing the flange to snapinto place. When locked together, the tapered cylinder 95 and retainer90 compress the O-rings 81, providing a resilient mount for connectingbody 80 when placed into grip 20 of handpiece 45 (see FIG. 4 b). Tabs 91on retainer 90 provide a secure mounting to the grip 20 of handpiece 45(see FIG. 4 b) with axial and rotational stability. Shoulder 92 providesa positive stop for mounting to allow the flow of water past thedimension D9 on retainer 90. Dimensions D8 is based on the diameter ofthe connecting body that is receiving the resilient mount. Typicaldimensions for D8 are 0.145 to 0.155 inches. The compression surface ontapered cylinder 95 for O-ring 81 is defined by the difference betweendimensions D6 and D7. The compression surface 93 on retainer 90 isdefined by the difference in dimensions D10 and D9.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canbe made to the present disclosure without departing from the scope ofthe same. While several embodiments of the disclosure have been shown inthe drawings, it is not intended that the disclosure be limited theretoas it is intended that the disclosure be as broad in scope as the artwill allow and that the specification be read likewise. Therefore, theabove description should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

What is claimed is:
 1. An ultrasonic instrument, comprising: a tipportion; a transducer configured to convert electrical energy intovibrational energy; an acoustic transformer interconnecting thetransducer and the tip portion; and a grip portion disposed at leastpartially about the acoustic transformer, the grip portion coupled tothe acoustic transformer via a resilient nodal coupling at a nodalregion of the acoustic transformer, the resilient nodal couplingconfigured to provide rotational and axial stability to the acoustictransformer.
 2. The instrument according to claim 1, wherein theresilient nodal coupling includes a resilient mount disposed at thenodal region of the acoustic transformer and a nest defined within thegrip, the nest configured to receive the resilient mount to couple thegrip portion and the acoustic transformer to one another.
 3. Theinstrument according to claim 2, wherein the resilient mount includes apair of opposed protrusions defined at the nodal region of the acoustictransformer and a resilient member disposed about each of theprotrusions.
 4. The instrument according to claim 3, wherein eachprotrusion defines a plurality of substantially flat surfaces configuredto interface with the resilient member.
 5. The instrument according toclaim 4, wherein the each protrusion defines a substantially squarecross-sectional configuration.
 6. The instrument according to claim 2,wherein the resilient mount includes a disk including a plurality ofslots defined at the nodal region of the acoustic transformer and aresilient member mounted on either side of the disk.
 7. The instrumentaccording to claim 2, wherein the resilient mount includes a taperedcylindrical member, a retainer, and at least one resilient member, thetapered cylindrical member configured for positioning about the acoustictransformer at the nodal region thereof, the retainer configured forslidable positioning about the tapered cylindrical member with theresilient member disposed therebetween.
 8. The instrument according toclaim 7, wherein the retainer and tapered cylindrical member are joinedvia a snap fit junction.
 9. The instrument according to claim 7, whereinthe retainer and tapered cylinder are joined via a threaded junction.10. The instrument according to claim 7, wherein the retainer andtapered cylinder are joined via a twist and lock bayonet junction. 11.The instrument according to claim 1, wherein the grip is formed at leastpartially from plastic.
 12. An ultrasonic instrument, comprising: a tipportion; a magnetostrictive transducer configured to convert electricalenergy into vibrational energy, the transducer formed from a pluralityof laminations, each lamination configured to define a plurality ofbending angles along a width dimension thereof, each lamination defininga length substantially equal to one-half wavelength at an operatingfrequency of the ultrasonic instrument; and an acoustic transformerinterconnecting the transducer and the tip portion, the tip portion andthe acoustic transformer cooperating to define a length substantiallyequal to one-half wavelength at the operating frequency of theultrasonic instrument.
 13. The instrument according to claim 12, whereinthe acoustic transformer defines a countersink at a proximal endthereof, the transducer configured for receipt within the countersink tosubstantially align the acoustic transformer relative to the transducer.14. The instrument according to claim 12, wherein each laminationdefines two bending angles, each bending angle equal to about 118degrees.
 15. The instrument according to claim 12, wherein eachlamination defines three bending angles, each bending angle equal toabout 136 degrees.
 16. The instrument according to claim 12, whereineach lamination defines a slot towards a distal end thereof, and whereina heat shrink material is disposed within the slots of the laminationsto secure the laminations to one another.
 17. The instrument accordingto claim 12, wherein each lamination defines a slot towards a distal endthereof, and wherein an end cap is disposed about the distal ends of thelaminations and engaged within the slots to secure the laminations toone another.
 18. The instrument according to claim 17, wherein the endcap is shaped to substantially conform to a shape of the proximal endsof the laminations.
 19. The instrument according to claim 12, whereineach lamination defines a hole towards the distal end thereof, andwherein a rivet is disposed through the holes of the laminations tosecure the laminations to one another.
 20. The instrument according toclaim 12, wherein transducer is encased within a sheath, and whereinedges of the transducer are tangent to an inner diameter of the sheath.21. The instrument according to claim 20, wherein the sheath is formedfrom a hollow extruded tubular member.
 22. The instrument according toclaim 20, wherein the sheath is formed from a two-piece molded part, thetwo-piece molded part including a nodal support located substantially ina nodal area of the transducer.
 23. An ultrasonic instrument,comprising: a tip portion; a transducer configured to convert electricalenergy into vibrational energy; an acoustic transformer interconnectingthe transducer and the tip portion; a grip portion disposed about aportion of the acoustic transformer and coupled to the acoustictransformer, the grip portion defining a gland area; a handpiecedisposed about a remaining portion of the acoustic transformer such thatthe grip portion and the handpiece cooperate to fully enclose theacoustic transformer, the handpiece defining an engagement areconfigured to receive the gland area of the grip portion; and anelongated sealing assembly interdisposed between the gland area of thegrip portion and the engagement area of the handpiece to rotatably andsealingly couple the grip portion and the handpiece to one another. 24.The ultrasonic instrument according to claim 23, wherein the sealingassembly includes an elongated sealing gasket defining a first endportion, a second end portion, and a central portion extending betweenthe first and second end portions, and wherein a diameter of at leastone of the first and second end portions is greater than a diameter ofthe central portion.
 25. The ultrasonic instrument according to claim24, wherein at least a portion of the engagement area of the handpiecedefines an internal diameter greater than the diameter of the centralportion of the sealing gasket.
 26. The ultrasonic instrument accordingto claim 23, wherein the sealing assembly includes an elongated sealinggasket and at least one ring member, the at least one ring memberdefining a diameter greater than a diameter of the sealing gasket. 27.The ultrasonic instrument according to claim 26, wherein the sealingassembly includes first and second ring members disposed at respectivefirst and second ends thereof, each ring member defining a differentdiameter greater than the diameter of the sealing gasket.
 28. Theultrasonic instrument according to claim 23, wherein the grip portion isrotatable relative to the handpiece through 360 degrees of rotation. 29.The ultrasonic instrument according to claim 23, wherein a requiredtorque for rotating the grip portion relative to the handpiece isbetween about 0.5 in-oz and about 1.5 in-oz.